Climate averages 1991–2020

Iwamizawa weather
in January.

A freezing month with moderate precipitation: the coolest and the 2nd driest of the year.

Long-term climate patterns, not a forecast for a particular trip.

Average high -3.5°C Daytime mean, January

Average low -10.8°C Night-time mean, January

Precipitation 49 mm 13 days with ≥1 mm

Daylight 9 h Sunrise to sunset, per day

January is a freezing month in Iwamizawa: daytime highs average -3.5°C and nights cool to about -10.8°C. By daytime temperature it is the coolest month of the year.

Expect about 49 mm of precipitation on roughly 13 days, which makes January a month with moderate precipitation (the 2nd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 9 h 23 min on an average January day.

The nearest other city in this atlas is Ebetsu (20 km away). In January its highs average -3.7°C, about as warm as Iwamizawa, with 41 mm of precipitation.

Among the 303 cities listed in Japan, Iwamizawa ranks 299th of 303 for the warmest January highs and joint 13th of 303 for the driest January (precipitation, lowest first). The mean January high of those 303 cities is 7.0°C; Iwamizawa is 10.4°C cooler than that mean.

From January to February, average highs rise by 1.0°C to -2.5°C, and monthly precipitation falls from 49 mm to 43 mm.

The annual picture

January in context

30-year average

Average highAverage low°C

Monthly precipitation

Average total · mm

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Iwamizawa climate table

1991–2020

Monthly climate averages for Iwamizawa, 1991–2020
Month	Average highHigh / low	Average low	Precipitation mm/month	Wet days ≥1 mm/day	Daylight hours/dayDaylight h/day
January, selected	-3.5°C-10.8°C	-10.8°C	49	12.9	9.49 h
February	-2.5°C-10.0°C	-10.0°C	43	10.8	10.510 h
March	1.9°C-5.9°C	-5.9°C	57	11.6	11.912 h
April	9.5°C0.1°C	0.1°C	67	11.8	13.413 h
May	16.2°C6.8°C	6.8°C	83	11.4	14.615 h
June	20.1°C11.8°C	11.8°C	64	9.6	15.315 h
July	23.7°C16.3°C	16.3°C	113	11.5	15.015 h
August	24.4°C17.5°C	17.5°C	161	12.5	14.014 h
September	20.8°C13.1°C	13.1°C	126	13.2	12.513 h
October	14.4°C6.3°C	6.3°C	92	13.6	11.111 h
November	6.7°C-0.5°C	-0.5°C	87	16.1	9.810 h
December	-0.8°C-8.0°C	-8.0°C	69	15.3	9.19 h

Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

January in nearby cities

Distance from Iwamizawa

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Iwamizawa) is explained once on the Iwamizawa year overview and on the Sources, method and limits page.